The Impact (8-2-2) had to play a man down when Alessandro Nesta was given a red card later in the half, but they still held on to take over the top spot in the Eastern Conference.

Sporting KC (6-5-4) lost for the first time in four MLS games.

Tempers that had been running hot the entire game threatened to spill over when it ended as the two teams met on the middle of the pitch. Sporting KC coach Peter Vermes got into a shouting match with several Impact players, and staff members from both sides had to keep the teams apart.

Sporting KC dominated possession, but the Impact had the better scoring chances.

Their best in the first half came when Felipe Martins got loose in the 39th minute. Nielsen strayed too far away from the goal and Martins sent a shot off the near post, and the ball deflected right back. Martins passed over to Marco Di Vaio, but his uncontested shot went wide left.

Sporting KC finally struck two minutes into stoppage time.

Nesta tugged on Bieler's jersey just outside of the penalty area, and may have actually pulled him a crucial step inside it. When Nesta yanked on Bieler once more, Sporting KC's leading scorer tumbled onto his rump, and referee Armando Villarreal awarded him a penalty kick.

Bieler poked it past Impact goalkeeper Troy Perkins for his seventh goal of the season.

It certainly didn't sit well with Montreal.

When the half ended, Schallibaum walked all the way to midfield and ripped into the referees over the penalty. The Impact coach then had harsh words with Nielsen as the two headed from the field, and Nielsen had to be restrained by a staff member as he headed up the tunnel for the locker room.

Schallibaum didn't appear at the start of the second half, the second time in two games against Sporting KC that the Impact coach has been dismissed this season.

He certainly missed quite the rally.

Early in the second half, Sporting KC's Mechack Jerome was given a yellow card for a reckless tackle, and Nyassi's shot from the top of the penalty area on the restart tied the game.

Just six minutes later, Sporting KC's Peterson Joseph whiffed while trying to clear the ball from in front of his goal, and Warner was there to punch it home and give the Impact a 2-1 lead.

Second-half substitute Benny Feilhaber nearly equalized for Sporting KC in the 66th minute when he sent a bicycle kick toward the net, but Perkins managed to deflect it away.

Perkins also saved a shot by Paulo Nagamura in the 71st minute.

A few minutes later, Nesta appeared to head-butt Bieler as they resumed their scrap from the first half. The match referee saw the clash of heads and Nesta was promptly shown a red card.

Sporting KC spent the final 20 minutes of the game pressing the attack against the short-handed Impact, but their defense proved stingy and Perkins was unflappable in the goal to ensure the win.